lfe132

Hello Everyone.
Can you tell me what it means when a car is "corner balanced"?
Thanks.
Larry

Peter Zimmermann

It is when the car is put on scales, and the left and right front are equal, and the left and right rear are equal. This, combined with accurate alignment and correct tire pressures, insures consistent cornering through left and right turns.

lfe132

Thank you Pete.
On a stock car, how far off is the balancing usually and what kind of weight is used to equalize?

Peter Zimmermann

The balance is usually well within 50 lbs +/- at each end. Ride height is used to correct imbalance, but only so much. After lowering a car to Euro ride height, for instance, if the technician did a really good job the weights will be within 20-30 lbs at the rear. Let's say that more weight is needed at the left rear, and the right front is too heavy compared to the left front. Raising the RF will transfer a small amount of weight to the LR, while at the same time reducing the weight at the RF. There will be times when the front is on the money, but the rear is still off between a few and maybe 15 pounds. That's when it's acceptable to use those adjustment bolts on the spring arms (they're large, and about 2/3 of the way forward toward the torsion bar end) to make minor ride height (weight adjustments) with. There is a bit of trial and error involved, and sometimes, short of re-indexing the rear torsion bars again, the car won't be perfect, but it will be close enough. If the rear ends up 50-100 pounds off, or more, side to side, then the torsion bars will have to be reset because one side is too low compared to the other side.

rbuswell

Pete, super answer as always. Can you tell us about the actual scales? Are they hard to source, expensive, etc.? Or are there ways to rent them or buy a good set for hobbyist purposes that won't break the bank?

Ed Hughes

A set of scales is not something a typical hobbyist will want to spring for. Dey ain't cheap.

They aren't hard to source, tons of speed shops sell them. I've never seen them for rent, there may be some here and there on a local basis-I doubt anyone would want to ship their scales much. The best thing to do is post on a forum to see if someone local may have them and would loan or rent.

Edgy01

Make friends with your local race shop. They will have a set of these. It's not a quick and easy thing to do so plan on spending a half day doing the setup.

KeithC2Turto

Adjustable drop links on your sway bars is a big help to achiving a good CB.

A good street and DE CB will be lf & rr total = 50% and the rf & lr total = 50% of the weight.
This will give simmilar handeling dynamics turning left or right.

Make sure they do it with your weight in the drivers seat.

Setting your front equal is for fender to fender racing for the best braking but may introduce some preload into one side.

altonj

On a 911 with its light front end, one should get equal LF and RF first above all else if the car is to be tracked. This allows for maximum braking. Sacrifice a wee bit on the rear if you have to so that the fronts are equal.

Fuel load throughout a day and whether or not a passenger is in the car all effects the CB too.

Ed is right, look for someone local to loan/rent a set. I loan mine out to local PCA types for free....

Cheers

KeithC2Turto

I am not an expert but what I understand if you go for equal front weights and if the net left total and net right total weights are not close there can be a couple of conciderations.

First is the amount of preload required to get the fronts equal may make the car handle a bit differently on right or left turns.

Second, if one dose this they should have a limited slip or they will risk having one of the rear wheels locking up early.

Equal front weights is a race setting for late braking when passing in fender to fender racing.

Both are valid approaches and a big improvement over a poorly ballanced car.

My car has a LSD and equal diagonals and I have not had issue w one front wheel locking, which was my concern. With the weight shift forward it dose not seem to be an issue on the track. More importantly for me seems to be to progressively brake to allow my stock front springs to load and the weight to shift forward in a controllable manner.

Honkity Hank

Here is how my 87 coupe worked out: It has LSD FWIW. This is really a bit of a compromise set up, more camber than normal for the street but not enough for the track. That said I find it fine at road atlanta on street tires, a bit more camber would help turn in but then stiffer t-bars will be needed too.

I had my 87 Carrera corner balanced and aligned. Posting the information for your reference.

Car is 100% stock.
Corner balance done with full fuel load (less maybe 2 gallons), spare tire, jack etc all installed. No adjustment for driver weight or other loading.

Setup is for street bias.

Ride ht is to fender lip.

Corner Balance Wt, Ride height.
LF: 599 lbs, 25.125" RF: 572 lbs, 25.125"
LR: 864 lbs, 25.375" RR: 864 lbs, 25.125"

Rake is about 0.75" when measured to sill trim.

Total weight 2,900 lbs.

Alignment spec Front: Caster 5.7 degrees, Camber -0.6 degrees, Toe 0.05"
Rear: Camber -1.0 degrees, Toe 0.05"